Catalyst system for polymerization of olefins

ABSTRACT

A process for producing an olefin polymer which comprises the homopolymerizing or copolymerizing an olefin in the presence of a catalyst system composed of an organoaluminum compound and a hydrocarbyloxy group-containing solid catalyst component which is prepared by 
     reducing a titanium compound represented by the general formula Ti(OR 1 ) n  X 4-n , wherein R 1  is a C 1  -C 20  hydrocarbon radical, X is halogen, and n is a number defined as 0&lt;n≦4, with an organoaluminum compound represented by the general formula AlR 2   m  Y 3-m , wherein R 2  is a C 1  -C 20  hydrocarbon radical, Y is halogen, and m is a number defined as 1≦m≦3, 
     subjecting the reduction product, which is a hydrocarbyloxy group-containing solid insoluble in hydrocarbon solvents, to a preliminary ethylene polymerization treatment, and 
     treating the resultant solid in a state of slurry in a hydrocarbon solvent with an ether compound and titanium tetrachloride at a temperature of 30° to 100° C.

This is a division of application Ser. No. 725,499, filed Apr. 22, 1985,now U.S. Pat. No. 4,645,808.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing an olefinpolymer.

2. Description of the Prior Art

It is well known that olefin polymers are produced generally by using aso-called ziegler-Natta catalyst comprising a transition metal compoundof groups IV to VI and either a metal or an organometallic compound ofgroups I to III. In particular, titanium trichloride compositions areused for industrial productions of polyolefins such as polypropylene,polybutene-1, etc. In such a production process, however, an amorphouspolymer is produced incidentally to a highly stereoregular olefinpolymer of great value for industrial utilization.

This amorphous polymer is of little value for industrial utilization andhas much detrimental effect on mechanical properties of the films,fibers, and other processed articles resulting from the olefin polymer,when contained therein in considerable amounts.

The formation of the amorphous polymer means a loss of the feed monomerand requires an additional production facility in order to remove theamorphous polymer, thus bringing about very significant disadvantagesalso in the industrial aspect.

Consequently, when such an amorphous polymer is not formed at all or islittle if any, it will be of very great advantage.

On the other hand, the olefin polymer produced in the abovepolymerization process contains catalyst residue, which causes problemsin the stability, processability, etc. of the olefin polymer. Therefore,facilities are necessary in order to remove the catalyst residue andstabilize the polymer.

This drawback will be removed by increasing the catalyst activityrepresented by the weight of the olefin polymer produced per unit weightof the catalyst. If the catalyst activity is increased to a greatextent, the facility for removing the catalyst residue will beunnecessary and the reduction of the polymer production cost will bepossible as well.

Methods for producing titanium trichloride include processes comprisingthe reduction of titanium tetrachloride (1) with hydrogen, followed bygrinding the reduction product in a ball mill to activate it, (2) withmetallic aluminum, followed by the same activation as above, and (3)with an organoaluminum compound at a temperature of -30° to +30°,followed by the heat treatment of the reduction product at a temperatureof 120° to 180° C. These processes, however, are unsatisfactory in boththe catalytic activity and the stereo-specificity of the producttitanium trichloride.

Further, the following processes have been proposed for producingtitanium trichloride: A process comprising treating the solid resultingfrom the reduction of titanium tetrachloride with an organoaluminumcompound, with a complexing agent, followed by reacting the resultantsolid with titanium tetrachloride (Japanese Patent Publication No.3356/78). A process comprising treating the above-mentioned solidreduction product with a complexing agent and titanium tetrachloride(Japanese Patent Publication No. 3480/79). A process comprising reducingan alkoxy group-containing titanium compound with an organoaluminumcompound in the presence of an ether compound, and adding titaniumtetrachloride and an ether compound to the reaction mixture to form aliquid state titanium compound, followed by heating the compound toreprecipitate a titanium compound (Japanese Patent Application Kokai(Laid-Open) Nos. 18608/81 and 20002/81).

The present inventors, as a result of intensive studies ofhydrocarbyloxy group-containing titanium compounds, found that acatalyst system composed of an organo aluminum compound and thefollowing solid catalyst component exhibits a high catalytic activityand gives a highly stereospecific olefin polymer (Japanese PatentApplication Kokai (Laid-open) No. 126,402/84). That is, the solidcatalyst component containing hydrocarbyloxy groups is prepared byreducing a titanium compound represented by the general formulaTi(OR¹)_(n) X_(4-n) with an organoaluminum compound, followed bytreating the resultant solid with an ether compound and titaniumtetrachloride.

According to this method, however, particles of the solid reductionproduct of the titanium compound represented by the formula Ti(OR¹)_(n)X_(4-n) disintegrate partially into fine particles during the activationtreatment with an ether compound and titanium tetrachloride. In themethods disclosed in Japanese Patent Application Kokai (Laid-Open) Nos.18608/81 and 20002/81, considerable amounts of fine particles are formedin the solid catalysts since a liquid state titanium compound is onceprepared. Accordingly, blocks are formed during the drying of the solidcatalyst after washing. When the block-containing solid catalyst is usedas such for olefin polymerization, clogging is liable to occur in thesolid catalyst feed line and particles of the polymer in thepolymerization reactor tend to aggregate into blocks, which may clog thepolymer discharge valve. Therefore, the screening of the solid catalystis necessary in order to remove the blocks.

SUMMARY OF THE INVENTION

For the purpose of preventing the disintegration of catalyst particlesin the activation treatment, the present inventors made intensivestudies, and as a result found that a highly active catalyst giving ahighly stereospecific olefin polymer results from a hydrocarbyloxygroup-containing solid catalyst component which is prepared by reducinga titanium compound represented by the general formula Ti(OR¹)_(n)X_(4-n) with an organoaluminum compound, and subjecting the resultingsolid product to a preliminary ethylene polymerization treatment,followed by treatment of the resultant solid with an ether compound andtitanium tetrachloride. Based on this finding, the present invention hasbeen accomplished.

Thus, the present invention relates to a process for producing an olefinpolymer which comprises homopolymerizing or copolymerizing an olefin inthe presence of a catalyst system composed of an organoaluminum compoundand a hydrocarbyloxy group-containing solid catalyst component which isprepared by reducing a titanium compound represented by the generalformula Ti(OR¹)_(n) X_(4-n), wherein R¹ is a C₁ -C₂₀ hydrocarbonradical, X is halogen, and n is a number defined as 0<n≦4, with anorganoaluminum compound represented by the general formula AlR² _(m)Y_(3-m), wherein R² is a C₁ -C₂₀ hydrocarbon radical, Y is halogen, andm is a number defined as 1≦m≦3, subjecting the reduction product whichis a hydrocarbyloxy group-containing solid insoluble in hydrocarbonsolvents to a preliminary ethylene polymerization treatment, andtreating the resultant solid in a state of slurry in a hydrocarbonsolvent with an ether compound and titanium tetrachloride at atemperature of 30° to 100° C.

According to the present invention, a highly active and highlystereospecific catalyst for olefin polymerization is obtained, the solidcomponent of which has good particle characteristics, that is, containsfew fine particles and few coarse particles. Hence, the catalyst of thepresent invention is characterized by offering an olefin polymer good inparticle characteristics, being free of fine or coarse particles.

Generally an electron donative compound is added to an olefinpolymerization system for the purpose of improving the stereospecificityof the olefin polymer. While the catalytic activity is generallydeteriorated in such a case, the deterioration scarcely occurs when thesolid catalyst component of the present invention is used. This isanother characteristic of the catalyst according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In the titanium compounds, used in the present invention, represented bythe general formula Ti(OR¹)_(n) X_(4-n) (R¹ : C₁ -C₂₀ hydrocarbonradicals; X: halogen; 0<n≦4), examples of R¹ are alkyls includingmethyl, ethyl, n-propyl iso-rpopyl, n-butyl, isobutyl, n-amyl, isoamyl,n-hexyl, n-heptyl, n-octyl, n-decyl, and n-dodecyl; aryls includingphenyl, cresyl, xylyl, and naphthyl; cycloalkyls including cyclohexyland cyclopentyl; propenyl and allyl; and aralkyl including benzyl. Ofthese, particularly preferred are linear alkyls of 2 to 18 carbon atomsand aryls of 6 to 18 carbon atoms.

A titanium compound having two or more different OR¹ groups can also beused.

Halogen atoms represented by X include, for example, chlorine, bromine,and iodine. Chrlorine as X gives specially favorable results.

The titanium compound of the general formula Ti(OR¹)_(n) X_(4-n) (0<n≦4)can be synthesized by a known method, for instance, by reacting Ti(OR¹)₄with TiX₄ in a prescribed ratio or by reacting TiX₄ with thecorresponding alcohol in a prescribed ratio.

Values of n of the titanium compounds represented by the general formulaTi(OR¹)_(n) X_(4-n) are defined as 0<n≦4, preferably 0.3≦n≦4, morepreferably 1≦n≦4, and most preferably 1.5≦n≦4.

Examples of the organoaluminum compounds, used for the reduction,represented by the general formula AlR² _(m) Y_(3-m) (R² : C₁ -C₂₀hydrocarbon radical; Y: halogen; 1≦m≦3) are ethylaluminumsesquichloride, dimethylaluminum chloride, diethylaluminum chloride,di-n-propylaluminum chloride, trimethylaluminum, triethylaluminum,triisobutylaluminum, ethyldichlorohexylaluminum, triphenylaluminum,diethylaluminum hydride, diisobutylaluminum hydride, diethylaluminumbromide, and diethylaluminum iodide. Of these compounds, diethylaluminumchloride and ethylaluminum sesquichloride give particularly favorableresults.

It is desirable to carry out the reduction in an inert hydrocarbonsolvent such as pentane, hexane, heptane, octane, decane, toluene, ordecalin in which the concentrations of the titanium compound and of theorganoaluminum compound are each from 10 to 70% by weight.

The reduction is carried out at a temperature of -10° to 80° C.,preferably 10° to 70° C., for a period usually of 1 to 6 hours, thoughthe reaction period is not particularly restricted.

The molar ratio of the organoaluminum compound to the titanium compoundin the reduction is freely varied according to the application purposeof the product olefin polymer. The molar ratios for favorable resultsare 0.5:1 to 1.5:1 in the case of diethylaluminum chloride and 1.5:1 to2.5:1 in the case of ethylaluminum sesquichloride.

After completion of the reduction, an additional reaction also may beconducted at a temperature of 30° to 100° C.

Hydrocarbyloxy group contents in the solid product obtained by reductioninsoluble in hydrocarbon solvents are 0.3 to 2.5 moles, preferably 0.4to 2.0 moles, particularly preferably 0.6 to 1.8 moles, per mole oftitanium atoms contained in the solid product.

The wide-angle X-ray diffraction pattern of this solid product taken byusing the X-ray Cu-Kα shows no peak characteristic of titaniumtrichloride crystal in the 2θ range of 10° to 60°, proving that theproduct is amorphous.

When the hydrocarbyloxy group content in this solid product is less thanthe above defined lower limit, the resulting solid catalyst component isunsatisfactory in catalytic activity and stereospecificity. On thecontrary, when the content exceeds the upper limit, the resulting solidcatalyst component is inferior in particle characteristics.

The hydrocarbyloxy group-containing, hydrocarbon-insoluble solid productobtained by the reduction can be subjected, as such without separatingfrom the mother liquid, to a preliminary ethylene polymerizationtreatment under ordinary polymerization conditions but without addingany organoaluminum compound. Preferably, the preliminary ethylenepolymerization treatment of the solid product obtained by reduction iscarried out, after it has been separated from the mother liquid andwashed several times with an inert liquid hydrocarbon such as pentane,hexane, heptane, octane, decane, toluene, xylene, or decalin. Thepreliminary polymerization treatment is conducted in the followingmanner: For example, 10 g of the hydrocarbyloxy group-containing solidproduct is suspended in 20 to 200 ml of an inert liquid hydrocarbon suchas hexane or heptane, 0.1 to 20 g of the same organoaluminum compound(0.1 to 20 g) as used in the main polymerization is added, and ethyleneis added and polymerized at a temperature of 20° to 80° C., preferably25° to 60° C., and a pressure of 0 to 10 Kg/cm² gage for a periodgenerally of about 5 minutes to 10 hours. Addition of hydrogen forregulating the molecular weight is possible at the preliminarypolymerization treatment. The amount of ethylene polymerized in thistreatment is in the range of 0.03 to 10 g, preferably 0.08 to 5 g,particularly preferably 0.15 to 3 g, per 1 g of the hydrocarbyloxygroup-containing solid product.

The molecular weight of the resulting ethylene polymer expressed inintrinsic viscosity [η] is preferably at least 1. The solid product ofthe preliminary polymerization treatment is separated from the liquid,and washed several times with an inert liquid hydrocarbon such as hexaneor heptane.

The solid product obtained by the preliminary polymerization treatment(hereinafter referred to as the preliminary polymerization treatedsolid) is then reacted with an ether compound and titanium tetrachloridein a hydrocarbon solvent.

Suitable ether compounds for this reaction are dialkyl ethers, e.g.diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether,di-n-amyl ether, diisoamyl ether, dineopentyl ether, di-n-hexyl ether,di-n-octyl ether, methyl n-butyl ether, methyl isoamyl ether, and ethylisobutyl ether. Di-n-butyl ether and diisoamyl ether are preferred inparticular.

The amount of ether compound used in this reaction is from 0.1 to 5moles, preferably from 0.3 to 3 moles, per mole of titanium atomscontained in the preliminary polymerization treated solid.

The amount of titanium tetrachloride for use is from 0.1 to 10 moles,preferably from 0.5 to 5 moles, per mole of titanium atoms contained inthe preliminary polymerization treated solid, and is from 0.5 to 10moles, preferably from 1.5 to 5 moles, per mole of the ether compound.

The reaction of the hydrocarbon-insoluble preliminary polymerizationtreated solid with the ether compound and titanium tetrachloride iscarried out in a slurry state.

Suitable liquids as media for this slurry include aliphatichydrocarbons, e.g. pentane, hexane, heptane, octane, and decane;aromatic hydrocarbons, e.g. toluene, xylene, and decalin; and alicyclichydrocarbons, e.g. cyclohexane and methylcyclohexane. Of thesehydrocarbons, particularly preferred are aliphatic hydrocarbons.

The solid concentration in the slurry is from 0.05 to 0.5 g/cm³,preferably from 0.1 to 0.3 g/cm³.

The reaction is carried out at a temperature of 30° to 100° C.,preferably 45° to 90° C., for a period of 30 minutes to 6 hours, thoughthe reaction period is not particularly restricted.

For mixing feed materials for this reaction, either the ether compoundand titanium tetrachloride may be added to the preliminarypolymerization treated solid or reversely the solid may be added to anether compound-titanium tetrachloride solution.

In the former addition manner, it is preferred to add titaniumtetrachloride after addition of the ether compound or to add the ethercompound simultaneously with titanium tetrachloride.

This reaction also may be conducted repeatedly twice or more.

Further the reaction can also be carried out in the presence of anelectron donative compound selected from nitrogen-, oxygen-, sulfur-,and/or phosphorus-containing organic compounds.

Representative electron donative compounds for use in this case include;ethers, specially, aromatic ethers e.g. diphenyl ether and anisole;siloxanes, e.g. dimethylsiloxane; thioethers, e.g. butyl sulfide;amines, specially tertiary amines, e.g. trioctylamine; and phosphoricesters, e.g. butyl phosphate.

The amount of the electron donative compound to be used is from 5×10⁻³to 0.5 mole, preferably from 1×10⁻² to 0.1 mole, per mole of titaniumatoms contained in the preliminary polymerization treated solid.

The solid catalyst component prepared in the present invention containshydrocarbyloxy groups in an amount of 5×10⁻⁴ to 2×10⁻¹ mole, preferably1×10⁻³ to 1.5×10⁻¹ mole, per mole of titanium atoms contained.

When the content of hydrocarbyloxy groups exceeds the above upper limit,the catalytic activity lowers and the resulting α-olefin polymer has lowstereospecificity.

On the contrary, when the content of hydrocarbyloxy groups is less thanthe above lower limit, the catalytic activity is particularly lowered.

The solid catalyst component resulting from the above reaction isseparated from the mother liquid, and washed several times with an inertliquid hydrocarbon solvent such as hexane or heptane to use forpolymerization.

Suitable organoaluminum compounds for use in olefin polymerization inthe present invention are trialkylaluminums, dialkylaluminum hydrides,dialkylaluminum chlorides, dialkylaluminum alkoxides, dialkylaluminumsiloxides, and mixtures of these compounds.

Individual examples thereof include dimethyl aluminum chloride,diethylaluminum chloride, diisobutylaluminum chloride, diethylaluminumbromide, diethylaluminum iodide, trimethylaluminum, triethylaluminum,triisobutylaluminum, diethylaluminum hydride, diethylaluminum ethoxide,and mixtures of these compounds. In particular, diethylaluminum chlorideand mixtures thereof with triethylaluminum are preferred.

The organoaluminum compound can be used in amounts widely ranging asfrom 0.1 to 500 moles per mole of titanium atoms contained in thehydrocarbyloxy group-containing solid catalyst component. The range of0.2 to 200 moles is preferable.

A known electron donative compound can be added to the polymerizationsystem so as to increase the stereospecificity of the polymer. Typicalexamples of such electron donative compounds are esters such as methylmethacrylate, ethyl benzoate, γ-butyrolactone, and ε-caprolactone, andphosphorous acid esters such as triphenyl phosphite and tri-n-butylphosphite.

The polymerization can be carried out at temperatures ranging from 0° to300° C. However, polymerization temperatures ranging from 0° to 100° C.are generally preferable in stereospecific polymerization of α-olefinsince high stereospecificity cannot be attained at polymerizationtemperatures above 100° C.

While the polymerization pressure is not particularly restricted,pressures of about 3 to 100 atm. are preferred from the industrial andeconomical point of view.

The polymerization may be conducted in a continuous or batchwiseoperation.

Olefins for which the present invention is adaptable are those having 2to 10 carbon atoms, for example, ethylene, propylene, butene-1,pentene-1, 4-methylpentene-1, and hexene-1. Particularly preferredthereof is propylene.

In the present invention, these olefins can be either homopolymerized orcopolymerized.

Copolymerization of two or more of these olefins can be carried out bycontacting the olefins in mixture with the catalyst system.

Heteroblock copolymerization, wherein polymerization is carried out intwo or more stages, is also possible in the present invention.

The polymerization can be accomplished by any of; the slurrypolymerization process using an inert hydrocarbon solvent such asbutane, pentane, hexane, heptane, or octane; solution polymerizationprocess comprising polymerization of an olefin in an inert hydrocarbonsolvent dissolving the formed olefin polymer; bulk polymerizationprocess comprising polymerization of an olefin in liquified form withoutusing any solvent; and gas phase polymerization process comprisingpolymerization of an olefin in the gaseous state.

For the purpose of controlling the molecular weight of the polymer,hydrogen or some other chain transfer agent can be added.

The process of the invention is illustrated with reference to thefollowing examples; however, the invention is not to be limited to theseexamples.

EXAMPLE 1 (A) Preparation of solid product

A 500-ml flask equipped with a stirrer and a dropping funnel, afterflushing with argon, was charged with 60 ml of n-heptane and 67 ml oftetra-n-butoxy-titanium. While keeping the inner temperature of theflask at 45° C., a solution of ethylaluminum sesquichloride (44.8 ml) inn-heptane (108 ml) was slowly added dropwise from the dropping funnelover 3 hours. Then the mixture was heated to 60° C., stirred for 1 hour,then left standing at room temperature, and subjected to solid-liquidseparation. The separated solid was washed four times with 100 ml ofn-heptane, and dried under reduced pressure, to give 38 g of a red-brownsolid product. Titanium and n-butoxy group contents per 1 g of thissolid product were 5.2 mmoles and 6.3 mmoles, respectively.

No peak characteristic of titanium trichloride crystal was observed inthe X-ray (Cu-Kα) diffraction pattern of the solid product, proving theamorphous structure thereof.

(B) Preparation of preliminary polymerization treated solid

A 300-ml flask equipped with a stirrer, after flushing with argon, wascharged with 241 ml of n-heptane, 0.34 g of triethylaluminum, and 24.1 gof a portion of the solid product prepared in (A) above. While stirringthe suspension at 50° C., ethylene was slowly fed thereto during 20minutes with the partial pressure being maintained at 0.2 Kg/cm² G, toaccomplish the preliminary polymerization treatment. Then the solid wasseparated from the liquid, washed twice with 50 ml of n-heptane, anddried under reduced pressure to give 26.5 g of a preliminarypolymerization treated solid. The amount of ethylene polymerized was 0.1g per 1 g of the solid product used.

(C) Preparation of solid catalyst component

A 100-ml flask, flushed with argon, was charged with 10.5 g of a portionof the preliminary polymerization treated solid prepared in (B) above,and 40.5 ml of n-heptane. While keeping the inner temperature of theflask at 30° C., 9.3 ml of diisoamyl ether was added to react with thesolid. After conducting the reaction at 30° C. for 1 hour, thetemperature was raised to 75° C. and 8.5 ml of titanium tetrachloridewas added to react with the solid. The reaction was continued at 75° C.for 1 hour. The resulting mixture was left standing at room temperature,and subjected to solid-liquid separation. The separated solid was washedfour times with 50 ml of n-heptane, and dried under reduced pressure togive a solid catalyst component.

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 5.0 mmoles and 0.27 mmole, respectively.

This solid catalyst component was good in particle characteristics. Noneof too fine particles and large aggregates were observed therein.

(D) Polymerization of propylene

A 130-ml stainless steel autoclave equipped with a magnetic stirrer,after flushing with argon, was charged with 250 mg of diethylaluminumchloride, 12.4 mg of a portion of the solid catalyst component preparedin (C) above, and 80 ml of liquified propylene.

The inner temperature of the autoclave was kept at 60° C. for 1 hourwith stirring. The excess of propylen was discharged. The reaminingproduct was air-dried for overnight to yield 16.9 g of a polypropylene.

Accordingly, the polypropylene yield (g) per 1 g of the solid catalystcomponent (hereinafter this yield is abbreviated as PP/cat) was 1360(PP/cat=1360).

The percentage of the polymer remaining after 6 hours' extraction of theobtained polypropylene powder with boiling n-heptane (hereinafter thispercentage is abbreviated as IY(%)) was 96.8% (IY=96.8%).

Particle size distribution of the obtained polypropylene powder is shownin Table 1. The content of fine particles less than 105μ in particlediameter was extremely low (0.14 wt%) and none of blocks larger than1000μ particle diameter were observed. Thus the polypropylene was goodin particle characteristics.

                                      TABLE 1                                     __________________________________________________________________________    Particle size distribution of polypropylene powder                                   Smaller                                                                            μ≦                                                                      149μ≦                                                                   250μ≦                                                                   297μ≦                                                                   350μ≦                                                                   420μ≦                                                                   590μ≦                                                                   710μ≦                                                                   Larger                                   than D<  D<  D<  D<  D<  D<  D<  D<  than                                     105μ                                                                            149μ                                                                           250μ                                                                           297μ                                                                           350μ                                                                           420μ                                                                           590μ                                                                           710μ                                                                           1000μ                                                                          1000μ                          __________________________________________________________________________    Example 1                                                                            0.14%                                                                              0.19%                                                                             2.3%                                                                              29.6%                                                                             52.7%                                                                             12.7%                                                                             1.9%                                                                              0.4%                                                                              0   0                                 Comparative                                                                          6.7% 7.1%                                                                              18.2%                                                                             15.5%                                                                             25.5%                                                                             14.8%                                                                             6.1%                                                                              1.4%                                                                              1.3%                                                                              3.4%                              Example 1                                                                     __________________________________________________________________________     (Note)                                                                        D: particle size of polypropylene powder                                 

COMPARATIVE EXAMPLE 1

A 100-ml flask, flushed with argon, was charged with 9.6 g of a portionof the solid product prepared in (A) of Example 1 and 36.9 ml ofn-heptane. While keeping the inner temperature of the flask at 30° C.,8.6 ml of diisoamyl ether was added to treat the solid. After treatmentat 30° C. for 1 hour, the resulting mixture was heated to 75° C.Titanium tetrachloride (11.7 ml) was added and reacted for 1 hour at thesame temperature. The resulting mixture was left standing at roomtemperature, and subjected to solid-liquid separation. The separationsolid was washed four times with 50 ml of n-heptane, and dried underreduced pressure to give a solid catalyst component.

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 5.4 mmoles and 0.29 mmole, respectively.

Considerable amounts of too fine particles and of large aggregates wereobserved in this solid catalyst component.

Using 8.4 mg of this solid catalyst component, propylene was polymerizedin the same manner as in (D) of Example 1. The results showedPP/cat=1260 and IY=96.1%.

Particle size distribution of the obtained polypropylene powder, asshown in Table 1, indicated that the powder contained 6.7% by weight offine particles smaller than 105μ in diameter and 3.4% by weight ofblocks larger than 1000μ in diameter.

EXAMPLE 2

A solid catalyst component was prepared in the same manner as in (A),(B), and (C) of Example 1 except that 7.0 ml of di-n-butyl ether wasused in place of diisoamyl ether in (C).

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 4.9 mmoles and 0.35 mmole, respectively.

The solid catalyst component was good in particle characteristics:neither too fine particles nor large aggregates were observed therein.

Using 13.2 mg of this solid catalyst component, propylene waspolymerized in the same manner as in (D) of Example 1. The resultsshowed PP/cat=1000 and IY=96.2%. In the obtained polypropylene powder,the content of fine particles less than 105μ in diameter was as low as0.05% by weight and no block larger than 1000μ in diameter was observed.Thus, this polypropylene was good in particle characteristics.

COMPARATIVE EXAMPLE 2

A solid catalyst component was prepared in the same manner as inComparative Example 1 except that 7.9 ml of di-n-butyl ether was used inplace of diisoamyl ether.

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 5.4 mmoles and 0.38 mmole, respectively. Considerableamounts of too fine particles and large aggregates were observed in thissolid catalyst component.

Using 16.9 mg of this solid catalyst component, propylene waspolymerized in the same manner as in (D) of Example 1. The resultsshowed PP/cat=1110 and IY=96.1%.

The obtained polypropylene powder was found to contain 7.9% by weight offine particles smaller than 105μ in diameter and 4.6% by weight ofblocks larger than 1000μ in diameter.

EXAMPLE 3 (A) Preparation of solid product

A 500-ml flask equipped with a stirrer and with a dropping funnel, afterflushing with argon, was charged with 83 ml of n-heptane, 16.1 ml oftitanium tetrachloride, and 51.0 ml of tetra-n-butoxytitanium. Whilestirring the mixture at 20° C., a solution of diethylaluminum chloride(37.8 ml) in n-heptane (162.1 ml) was slowly added dropwise from thedropping funnel over 3 hours. Then, the mixture was heated to 50° C.,stirred for 1 hour, then left standing at room temperature, andsubjected to solid-liquid separation. The separated solid was washedfour times with 200 ml of n-heptane, and dried under reduced pressure togive 64.7 g of a red-brown solid product.

Titanium and n-butoxy group contents per 1 g of this solid product were5.3 mmoles and 4.8 mmoles, respectively.

No peak characteristic of titanium trichloride crystal was observed inthe X-ray (Cu-Kα) diffraction pattern of the solid product, proving theamorphous structure thereof.

(B) Preparation of preliminary polymerization treated solid

A portion (19.7 g) of the solid product prepared in (A) above wassubjected to preliminary ethylene polymerization treatment in the samemanner as in (B) of Example 1. The amount of ethylene polymerized was0.09 g per 1 g of the solid product.

(C) Preparation of solid catalyst component

A 100-ml flask, flushed with argon, was charged with 9.9 g of a portionof the preliminary polymerization treated solid prepared in (B) aboveand 38 ml of n-heptane. While keeping the inner temperature of the flaskat 30° C., 8.5 ml of diisoamyl ether was added to treat the solid. Aftertreatment at 30° C. for 1 hour, the mixture was heated to 80° C. and11.5 ml of titanium tetrachloride was added to react with the solid. Thereaction was continued at 80° C. for 1 hour. The resulting solid wasseparated from the liquid, washed four times with 50 ml of n-heptane,and dried under reduced pressure to give a solid catalyst component.

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 5.0 mmoles and 0.22 mmole, respectively.

This solid catalyst component was good in particle characteristics. Noneof too fine particles and large aggregates were observed therein.

(D) Polymerization of propylene

Using 14.5 mg of the solid catalyst component prepared in (C) above,propylene was polymerized in the same manner as in (D) of Example 1. Theresults showed PP/cat=1610 and IY=98.2%. In the obtained polypropylenepowder, the content of fine particles less than 105μ in diameter was aslow as 0.08% by weight and no block larger than 1000μ in diameter wasobserved.

EXAMPLE 4

A 100-ml flask, flushed with argon, was charged with 12.1 g of a portionof the preliminary polymerization treated solid prepared in (C) ofExample 1 and 42.3 ml of n-heptane. While keeping the inner temperatureof the flask at 30° C., 14.4 ml of diisoamyl ether was added to treatthe solid. After treatment at 30° C. for 1 hour, the mixture was heatedto 75° C., and 15.7 ml of titanium tetrachloride was added to react withthe solid. The reaction was continued at 75° C. for 1 hour. Theresulting solid was separated from the liquid, washed four times with 50ml of n-heptane, and dried under reduce pressure to give a solidcatalyst component.

Titanium and n-botoxy group contents per 1 g of this solid catalystcomponent were 5.1 mmoles and 0.08 mmole, respectively.

This solid catalyst component was good in particle characteristics.

Using 14.1 mg of this solid catalyst component, propylene waspolymerized in the same manner as in (D) of Example 1. The resultsshowed PP/cat=1800 and IY=98.2%. In the obtained polypropylene powder,the content of fine particles smaller than 105μ in diameter was as lowas 0.05% by weight and no block larger than 1000μ in diameter wasobserved.

EXAMPLE 5

A 100-ml flask, flushed with argon, was charged with 10.1 g of apreliminary polymerization treated solid prepared in the same manner asin (B) of Example 1 and 39.0 ml of n-heptane. While keeping the innertemperature of the flask at 30° C., 9.6 ml of diisoamyl ether and 0.2 mlof tri-n-octylamine were added to treat the solid. After treatment at30° C. for 1 hour, the temperature was raised to 75° C., and 12.8 ml oftitanium tetrachloride was added to react with the solid. The reactionwas continued at 75° C. for 1 hour. The resulting solid was separatedfrom the liquid, washed four times with 50 ml of n-heptane, and driedunder reduced pressure to give a solid catalyst component.

Titanium and n-butoxy group contents per 1 g of this solid catalystcomponent were 4.9 mmoles and 0.26 mmole, respectively. This solidcatalyst component was found to have good particle characteristics.

Using 13.9 mg of this solid catalyst component, propylene waspolymerized in the same manner as in (D) of Example 1.

The results showed PP/cat=1400 and IY=96.3%. In the obtainedpolypropylene powder, the content of fine particles smaller than 105μ indiameter was as low as 0.20% by weight and no block larger than 1000μ indiameter was observed.

EXAMPLE 6 (A) Preparation of solid product

A 300-ml flask equipped with a stirrer and with a dropping funnel, afterflushing with argon, was charged with 15 ml of toluene and 15 ml oftitanium tetrachloride. While keeping the inner temperature of the flaskat 80° C., a mixture comprising 40 ml of toluene and 28.7 ml of o-cresolwas slowly added dropwise from the dropping funnel over 1 hour.Thereafter, the resulting mixture was further stirred at 80° C. for 1.5hours.

The inner temperature of the flask was lowered to 20° C. and then asolution of diethylaluminum chloride (17 ml) in n-heptane (40 ml) wasslowly added dropwise from the dropping funnel over 2 hours whilekeeping the temperature at 20° C. Thereafter, the resulting mixture wasfurther stirred for 1 hour, and left standing at room temperature toseparate into solid and liquid. The separated solid was washed 6 timeswith 100 ml of n-heptane, and dried under reduced pressure to give abrown solid product.

Titanium and o-cresyloxy group contents per 1 g of this solid productwere 4.3 mmoles and 3.9 mmoles, respectively.

No peak characteristic of titanium trichloride crystal was observed inthe X-ray (Cu-Kα) diffraction pattern of this solid product, proving theamorphous structure thereof.

(B) Preparation of preliminary polymerization treated solid

Using 18.3 g of the solid product obtained in (A) above, a preliminarypolymerization treated solid was prepared in the same manner as in (B)of Example 1. The amount of ethylene polymerized was 0.2 g per 1 g ofthe solid product used.

(C) Preparation of solid catalyst component

A 100-ml flask, flushed with argon, was charged with 7.6 g of a portionof the preliminary polymerization treated solid prepared in (B) aboveand 29.2 ml of n-heptane. While keeping the inner temperature of theflask at 30° C., 5.7 ml of diisoamyl ether was added to treat the solid.After treatment at 30° C. for 1 hour, the temperature was raised to 75°C., and 7.7 ml of titanium tetrachloride was added to react with thesolid. The reaction was continued at 75° C. for 1 hour. Then, theresulting solid was separated from the liquid, washed four times with 50ml of n-heptane, and dried under reduced pressure to give a solidcatalyst component.

Titanium and o-cresyloxy group contents per 1 g of this solid catalystcomponent were 3.4 mmoles and 0.14 mmole, respectively.

This solid catalyst component was found to have good particlecharacteristics.

(D) Polymerization of propylene

Using 14.5 mg of the solid catalyst component prepared in (C) above,propylene was polymerized in the same manner as in (D) of Example 1. Theresults showed PP/cat=870 and IY=96.9%. The obtained polypropylenepowder was good in particle characteristics; the content of fineparticles smaller than 149μ in diameter was as low as 0.1% by weight andno block larger than 1000μ in diameter was observed.

EXAMPLE 7

Polymerization in liquefied propylene

A 1-liter stainless steel autoclave equipped with stirrer, afterflushing with argon, was charged with 1.5 g of diethylaluminum chloride,29.5 mg of a portion of the solid catalyst component prepared in Example4, and then with hydrogen in an amount corresponding to a partialpressure of 0.6 Kg/cm² G and further with 280 g of liquefied propylene.The temperature of autoclave was raised to 65° C., and polymerization ofpropylene was continued at 65° C. for 2 hours. Thereafter, the unreactedmonomer was purged, and the formed polymer was dried under reducedpressure at 60° C. for 2 hours to give 147.6 g of a polypropylenepowder. Accordingly, PP/cat was 5000. The proportion of the atacticcomponent soluble in cold xylene was 1.7% by weight of the total yieldedpolymer. The obtained polypropylene powder containing no coarse or fineparticles was good in particle characteristics.

EXAMPLE 8 Random copolymerization of ethylene and propylene

A 5-liter stainless steel autoclave equipped with a stirrer, afterflushing with argon, was charged with 1.5 l of dry n-heptane and 6.0 mgof ε-caprolactone. Succeedingly, hydrogen and ethylene were added inamounts corresponding to partial pressures of 0.20 and 0.095 Kg/cm² G,respectively. The temperature of autoclave was raised to 60° C.Propylene was fed into the autoclave to a total pressure of 4 Kg/cm² G,and then 1.5 g of diethylaluminum chloride and 132.7 mg of a portion ofthe solid catalyst component prepared in Example 4 were added toinitiate polymerization. The polymerization was continued for 4 hourswhile keeping the total pressure at 4 Kg/cm² G by supplying anethylene-propylene mixed gas containing 6.5% by volume of ethylene.Thereafter, the introduction of the mixed gas was stopped and theunreacted monomers were purged. The formed copolymer was filtered on aBuchner funnel, and dried at 60° C. to give 359 g of anethylene-propylene copolymer powder. The filtrate was evaporated toremove n-heptane to give 7.9 g of an amorphous polymer. Accordingly, theheptane-insoluble polymer content (HIP) was 97.8%. The copolymer yieldper 1 g of the solid catalyst component (PP/cat) was 2760. Infraredabsorption spectroscopy indicated that 3.6% by weight of ethylene wascontained in the copolymer. The proportion of the atactic componentsoluble in cold xylene was 4.0% by weight of the total copolymer powder.

EXAMPLE 9 Block copolymerization of ethylene and propylene

A 5-liter stainless steel autoclave equipped with a stirrer, afterflushing with argon, was charged with 98.8 mg of a portion of the solidcatalyst component prepared in (C) of Example 1 and 3.0 g ofdiethylaluminum chloride. Then, hydrogen gas was added in an amountcorresponding to a partial pressure of 0.79 Kg/cm² G. Subsequently 1.3Kg of propylene was forced into the autoclave to be polymerized. Thepolymerization was continued for 1 hour while keeping the autoclavetemperature at 60° C.

Thereafter, the unreacted monomer was purged, and the gas in theautoclave was replaced again with argon. While keeping the temperatureat 60° C., hydrogen in an amount corresponding to a partial pressure of0.15 Kg/cm² G was added, propylene gas was fed to a total pressure of8.0 Kg/cm² G, and ethylene gas to a total pressure of 10 Kg/cm² G, tostart gas phase copolymerization.

The gas phase copolymerization of ethylene and propylene was continuedfor 3.0 hours while supplying a 50:50 vol % ethylene-propylene mixed gasso as to maintain the total pressure of 10 Kg/cm² G.

Then, the unreacted monomer was purged to give 465 g of apropylene-ethylene block copolymer, free of fine and coarse particles,good in particle characteristics.

This block copolymer was found to contain 63% by weight of propylenehomopolymer and 37% by weight of propylene-ethylene copolymer.

COMPARATIVE EXAMPLE 3 (A) Preparation of solid catalyst component

A 300-ml flask was flushed with argon. Then, 70 ml of n-heptane andn-butoxytitanium trichloride (100 mmoles, prepared by mixing 75 mmolesof TiCl₄ and 25 mmoles of Ti(OBu)₄) were placed in the flask. Whilestirring the mixture at 30° C., 50 mmoles of n-butyl ether was addeddropwise. Then diethylaluminum chloride (95 mmoles, in toluene at aconcentration of 1 mole/l) was added dropwise at 60° C. over 1 hour. Theformed precipitate was filtered, washed three times with 100 ml ofn-heptane, and dried under reduced pressure to give 17 g of a red-brownsolid.

Then, 8.1 g of a portion of this solid together with 20.3 mmoles oftitanium tetrachloride, 20.3 ml of toluene, and 20.3 mmoles ofdi-n-butyl ether was charged into a 100-ml flask which had been flushedwith argon, and was dissolved with stirring at 60° C. for 1 hour to forma black-brown liquid. This liquid was further stirred at 100° C. for 4hours to allow reaction to proceed. Filtration of the thus formedprecipitate was tried by using a G-3 glass filter but was impossiblebecause of heavy clogging of the filter. Therefore a dip tube was usedto separate the solid from the liquid. The separated solid was washedfour times with 50 ml of n-heptane, and dried under reduced pressure togive 6.3 g of a solid catalyst component.

(B) Polymerization of propylene

Using 20.6 mg of the solid catalyst component prepared in (A) above,propylene was polymerized in the same manner as in (D) of Example 1. Theresults showed PP/cat=450 and IY=97.1%.

The obtained polypropylene powder was found to contain 37.0% by weightof fine particles smaller than 105μ in diameter and 1.8% by weight ofblocks larger than 1000μ in diameter.

EXAMPLE 10 Polymerization of propylene

A 5-liter stainless steel autoclave equipped with a stirrer, afterflushing with argon, was charged with 1.5 l of dry n-heptane, 1.5 g ofdiethylalauminum chloride, 105.8 mg of a solid catalyst componentprepared in the same manner as in Example 4, and 29.7 mg ofε-caprolactone, and subsequently with hydrogen in an amountcorresponding to a partial pressure of 0.395 Kg/cm² G and further with130 g of liquefied propylene to polymerize propylene. The polymerizationwas conducted at 60° C. for 4 hours while supplying propylene gas so asto keep a total pressure of 6 Kg/cm² G. Then, the introduction ofpropylene gas was stopped, and the unreacted monomer was purged. Theresulting polymer was filtered on a Buchner funnel, and dried at 60° C.to yield 250.9 g of a polypropylene powder. The filtrate was evaporatedto remove n-heptane, to give 2.0 g of an amorphous polymer.

Accordingly, the HIP was 99.2%. The PP/cat was 2390. The proportion ofthe atactic component soluble in cold xylene was 1.1% by weight of thepolymer powder. The obtained polypropylene powder was free of fine andcoarse particles, thus being good in particle characteristics.

EXAMPLE 11 Polymerization of propylene

Propylene was polymerized in the same manner as in Example 10 exceptthat no ε-caprolactone was added. The results showed PP/cat=2480 andHIP=98.9%. The proportion of the atactic component soluble in coldxylene was 2.0% by weight. The obtained polypropylene powder was free offine and coarse particles, good in particle characteristics.

What is claimed is:
 1. A catalyst system for polymerization of olefinswhich comprises:(A) a hydrocarbyloxy group-containing solid catalystcomponent which is prepared by reducing a titanium compound representedby the general formula Ti(OR¹)_(n) X_(4-n), wherein R¹ is a C₁ -C₂₀hydrocarbon radical, X is halogen, and n is a number defined as 0<n≦4,with an organoaluminum compound represented by the general formula AlR²_(m) Y_(3-m), wherein R¹ is a C₁ -C₂₀ hydrocarbon radical, Y is halogen,and m is a number defined as 1≦m≦3, subjecting the reduction product,which is a hydrocarbyloxy group-containing solid insoluble inhydrocarbon solvents and in which the hydrocarbyloxy group content is0.3 to 2.5 moles per mole of titanium atoms, to a preliminary ethylenepolymerization treatment, and treating the resultant solid in a state ofslurry in a hydrocarbon solvent with an ether compound and titaniumtetrachloride at a temperature of 30° to 100° C., and (B) anorganoaluminum compound.
 2. The catalyst system according to claim 1,wherein n of the titanium compound represented by the general formulaTi(OR¹)_(n) X_(4-n) is a number defined as 1≦n≦4.
 3. The catalyst systemaccording to claim 1, wherein X of the titanium compound represented bythe general formula Ti(OR¹)_(n) X_(4-n) is chlorine.
 4. The catalystsystem according to claim 1, wherein the hydrocarbon radical R¹ is alinear alkyl group of 2 to 18 carbon atoms and/or aryl groups of 6 to 18carbon atoms.
 5. The catalyst system according to claim 1, wherein theether compound is a dialkyl ether.
 6. The catalyst system according toclaim 1, wherein the amount of the ether compound used for the treatmentof the preliminary polymerization treated solid is from 0.1 to 5 molesper mole of titanium atoms contained in the solid.
 7. The catalystsystem according to claim 1, wherein the amount of titaniumtetrachloride used for the treatment of the preliminary polymerizationtreated solid is from 0.1 to 10 moles per mole of titanium atomscontained in the solid.
 8. The catalyst system according to claim 1,wherein the amount of hydrocarbyloxy groups in the solid catalystcomponent is from 5×10⁻⁴ to 2×10⁻¹ mole per mole of titanium atomscontained in the solid catalyst component.
 9. The catalyst systemaccording to claim 1, wherein the amount of ethylene preliminarilypolymerized is from 0.03 to 10 g per 1 g of the hydrocarbyloxygroup-containing solid reduction product.